Pre-heat the oven to 350°F.
Butter a 2-1/2-quart baking dish.
Cut the squash into 1/2-inch-thick slices.
Cook in boiling, salted water, until tender; about 10 minutes; drain.
Purée in a food processor.
In a medium skillet, over medium heat, melt 6 tablespoons of the butter; add the onion, garlic and peppers; cook until just tender.
Meanwhile, crumb the toast in a food processor; melt remaining butter and toss together.
Mix the squash purée, onions, peppers, garlic, cracker crumbs and cheese.
Stir in the eggs, cream, sugar and seasonings; blend well.
Pour into the baking dish.
Top with bread crumbs and bake until browned; about 40 minutes.